Cushioning mechanism for reciprocating beds.



No. 845,429. PATENTED FEB. 26, 1907. U. A. McGAIN. GUSHIONING MECHANISMFOR REGIPROGATING BEDS.

APPLICATION FILED MAR-5.1906.

3 SHEETS-SHEET 1.

. No. 845,429. PATENTED FEB. 26, 1907.

G. A. MGCAIN.

OUSHIONING MECHANISM FOR REGIPROOATING BEDS.

APPLIOATION FILED MAR-5.1906. 3 SHEETS-SHEET Z.

No. 845,429. PATENTED FEB. 26, 1907. G. A. MCCAIN.

GUSHIONING MECHANISM FOR RBOIPROUATING BEDS.

APPLICATION FILED MAR.5, 1906.

3 SHEETS-SHBBT 3.

" 'IIIIIINIIIHI I UNITED STATES CYRUS A. MCCAIN, OF CHICAGO, ILLINOIS.

PATENT OFFICE.

cusl-llowme. MECHANISM Fon' RECIPROCATING BEDS.

Specification of Letters Patent.

Patented Feb. 26, 1907.

Application filed March 5, 1906. Serial No. 304.287.

provement in Cushioning Mechanism for Iteciprocating Beds, of which thefollowing is a specification.

My invention relates to improvements in pneumatic cushioning means forreciprocating beds, and more especially for the beds ofprinting-presses. Y

My ob ect is to provide cushioning means of improved construction whichWill operate automatically to regulate the cushioning resistance inaccordance with the speed of reciprocation of the bed.

In carrying out my invention I provide pistons to enter cylinders in themovement of the bed toward the end of its traverse in each direction,either the pistons or the cylinders, and preferably the former, beingfastened to the bed to travel therewith. In either the pistons or thecylinders, preferably the former, I provide vent-openings of suitablesize governed by normally unseated valves of special construction and soarranged that they will remain open toprevent any cushioning action whenthe bed is reciprocated, as byv hand, at slow speed, and will close inthe more rapid reciprocation of the bed in a manner to initiate thecushioning resistance sooner or later, according to the speed ofreciprocation of the bed, thereby to properly regulate the degree ofcushioning.

have found in practice that to provide valves which will operate withnecessary certainty to produce the desired cushioning effect they mustbe of disk or ring form held normally open by springs of suitabletension and each present a large area, as compared with the are of thevent-opening which it governs, to the cylinder air con-' tents, in orderthat it may be suitably sensitive for the performance of its function.

In order that the operation of the valves may be under proper control,it is necessary that the pistons shall properly fit the cylinders, andfor this purpose I provide pistons of novel construction each with anadjustable packing-ring and improved adjusting means for thepacking-ring.

Referring to the drawings, Figure 1 is a broken sectional view showing acylinder and a piston of my im roved construction provided with the cus'oning-valve; Fig. 2, an

enlarged broken sectional view of the piston; I

big. :5, a face view of the piston intact; Fig.

4, a simi.ar view of the piston with the disk' or ring valve removed andshowing the adustab.e expanding means for the pistonpacking; ig. 5 asection, on a reduced scale f taken on line 5 in F i 2 and showing therear side of the piston; of the disk or ring valve, showing its seatingface, and Fig. 7.,an en.arged view of one of three segmental expandingmembers for the piston-packing.

The cylinder 8 has a closed end, or head 9,

and is of a form oommony employed in printing-presses. The piston-stemluhas a threaded end portion 11, on which the piston 12 is screwed andlocked against rotation by 1 a nut 13. The body of the piston consistsof a metal disk having a central externallythreaded hub or boss 14.Eq'uidistant around the hub are three or three-pairsof Fig. 6, a view ine.evation openings 15 through the piston, forming an annular series ofvent-ports, and between the' said openings the piston is formed withdeepsockets 16. The said sockets have annular shoulders 17, beyond whichthey are'formed with reduced threaded receptacles 18to hold I adjusting-screws 19. Surrounding the hub 14 is a disk or ring 20, havingperforations 2-1 to receive the screws 19, on which the ring is thusslidingly mounted and which form guides for the ring. The ring isprovided with seating projections 22, of rubber, leather, or the like,adapted to seat over and close the ventopenings 15. In the sockets .16are .coilsprings 23, confined between the shoulders 17 and the disk orring 20 and operating nor-.

mally to press the latter against the heads of 1 the guide and adjustingscrews 19.

Around the piston is a cupped, preferably leather, packing 24, formingthe peripheralv face of the piston and extending against the rear sidethereof around the openings 15 and socket projections described. Fittingagainst the packing at 'the rear side of the piston is va clamping-ring25, fastened thereto by means of screws 26, to clamp the packing inplace. I a

On the working face of theplston 18 packing-expanding means comprising acupped disk formed of relatively adjustable segmental members 27, havingthe peripheral flanges 28. The inner circular edges 29 of the segmentsare beveled, as shown, and the segments have cut-away portions 30 toclear the valve-seating projections 22 and elon- ITO ated openings'31and 32in the positions inicated. The openings 32 form guides, whichreceive-pins or studs 33, projecting from the adjacent face of thepiston. The openings 31 also form uides and receive fasteningescrews 34,which enter threaded sockets in the adjacent face of the piston andtighten the segments 27 in their adjusted position. The segments areprovided with outer slits 35 in their flanges 28 and slits 35*,extending from the cut-away portions 30' to give to the segments aspringy character whereby they may ex and and contract laterally. On thethreat ed boss 14 is a nut 36, formed into an annular wedge 37 to engagethe beveled inner ends of the segments. Turnin of the nut 36 in onedirection causes its we ge-shaped end to bear against the ends 29 andforce the segments radially outward. As the latter sl de upon the guides33 34 they are caused to stretch or expand slightly and fit perfectlyagainst the inner circumference of the packing 24. The guidescrews 34may be turned to fasten the segments securely in adjusted position. Thusit will be seen that byturning the nut 36 the packin 24 may be, expandedto fit with desired c oseness the cylinder 8, and in the event of wearof the packing it may be exanded from time to time to maintain its fitin the cylinder. Extending through the nut 36'is a set-screw 38 forfastening it against turning on the boss 14.

In ractice the packing is expanded to fit with esired closeness thecylinder 8 and the screws 19 are adjusted to normally position the diskor ring valve 20 under tension of the springs 23 at the desired distancefrom the seating faces of the ports or vent-openings 15. 'Ihe annularopening around t e disk or ring 20 should be of just the roper area topermit air to pass through to t e rear side of the disk or ring to theports 15 in a manner to, prevent air-pressure from closing the disk orring valve except when pressure accumulates 1n the cylinder faster thanit can vent around the disk or ring to the ports. The parts are adjustedwith relation tothe tension of the springs 23 by means of the screws 19,so that when the piston enters the cylinder at comparatively slow speedit will not be able to compress tl-e air therein to an extent whichwould efi'ect closing movement of the valve device. In a somewhat fastermovement of the piston into the cylinder the air will not be able toescape quite fast enough to compensate for the displacement of thepiston, and when the latter ap roaches nearly to the end 9 the pressurewill ave accumulated sufficiently to close the valve device, confiningthe remaining pressure for a comparatively slight cushioning purpose.The faster the piston moves on entering the cylinder the sooner,therefore, will the valve device be closed and the greater the cushion-'ng effect of the confined air. When running at the highest speed, mostof the air contained in the cylinder when the piston starts to enter maybe trapped to cushion the reciprocating bed. 1 Thus the degree ofcushioning will be governed entirely by the speed of reciprocation.

As before stated, I have found in practice that to effect the desiredresults with sufficient certainty the valve device should be constructedto operate substantially as shown and described, and no other valveconstruction of which I am aware will fulfil my object. Besidesoperating with reat certainty in producing the desired cus ioning effectit is practically noiseless in operation and self-contained. Itdispenses with pipes, cocks, and other attachments usually em loyed inother cushioning mean's intended or the same purpose. r

As I prefer to employ my improvements the cylinders are stationary andthe pistons reciprocate with the bed. The valve devices are thus more orless affected by momentum in their movement with the pistons. Thismomentum tends to quicken the closing and opening movements of thevalves at the beginning and end of the cushioning action, which I havefound to be an advantage.

A ring and a disk are the equivalents of each other as applied to thepart 20, which is shown to beof annular form merely to permit theemployment of the packing-adjusting nut 36 in the relative positionshown.

The slits 35 operate to render the flange portion 28 of the segmentsyielding, so that in the event that the packing is expanded undul it mayyield in passing into the cylinder an prevent its sticking or sliding inthe cylinder with too great friction. The shape of the packing 24 andthe construction of the parts 27 causes the packing while air is beingcompressed in the cylinder to be pressed by the air against the wall ofthe cylinder and produce at all times a properly-tight fit. At the sametime it leaves the annular edge of the sliding valve device free andpermits air to rush around all parts thereof equally and maintain thevalve properly balanced. Another advantage of m improved constructionlies'in'the fact t rat when the pistons start on their return strokes inthe direction away from the cylinder-heads the springs open the valvedevices before the pistons can commence to draw a vacuum. Thus even whenthe bed is reciprocating at highest speed there will at no time be anysuction action in the cylinders while valves are being opened, whichwould tend to retard free movement of the bed and attendant parts.

What I claim as new, and desire to secure by Letters Patent, is.

1. In a cushioning device'for reciprocating beds, the combination withcushioning members, one stationary and the other movable with the bed,and consisting of a piston and a cylinder, of cushion-regulating meanson one member comprising an annular series of ventports, a sliding,normally open ring or disk valve governing said vent-ports, guidingmeans for the valve, and spring controlling means for the valve actingcounter to pressure in the cylinder.

2. In a cushioning device for reciprocating beds, the combination withcushioning members, one stationary and the other movable with the bed,and consisting of a piston and a cylinder, of cushion-regulating meanson one member comprising an annular-series of ventports, a slidingnormally open ring or disk valve governing said vent-ports, guiding means for the valve, unseating springs for the valve acting counter topressure in the cylinder, and adjusting means for the springs.

3. In a cushioning device for reciprocating beds, the combination withcushioning members, one stationary and the other movable with the bed,and consisting of a piston and a c linder, an annular series ofvent-ports in t e c linder, a sliding ring or disk valve carried thepiston and governing said ventport t erein, guides on the piston onwhich the valve slides, and springs interposed between the piston andvalve acting counter to pressure in the cylinder.

4. The combination with a piston, of a circumferential packing carriedthereby, and means for expanding the packing, comprising a cup-shapeddisk on the piston formed of radiallyadjustable segmental members, in-

herently expansible and contractible to de- D scribe, atpacking-engaging surfaces, varying arcs at different positions ofadjustment, and means for forcing the segments outwardly against thepacking whereb 'the periphery of said cup-shaped disk will a ways heapproximately' circular.

5. The combination with a iston, of a circumferential packing carriethereby, and means for expanding the packing, comprising a cup-shapeddisk on the piston formed of radially-adjustable segmental members,inherently expansible and contractible to describe, at packing-engagingsurfaces, varying arcs at different positions of adjustment, means forforcing the segments outwardly against the packing, and me ans forexpanding the segments as they are forced in the outward directionwhereby the periphery of said cup-shaped disk will always beapproximately circular.

6. The combination with a piston, of a circumferential packing carriedthereby and means for expanding the packing, comprising a cup-shapeddisk on the piston formed of radially-adjustable segmental members,slitted to render them inherently expansible and contractible todescribe, at packing-engaging surfaces, varying arcs at differentpositions of adjustment, and means forforcing the segments outwardlyagainst the packing whereb the periphery of said cup-shaped disk willways be approximately circular.

- CYRUS A. MCCAIN.

In presence of- J. H. LANDES, L. HEISLAIL,

